1. Field of the Invention
The present invention relates to DNA fragments that confer resistance to porphyrin-accumulating type herbicides on plant and algal cells, plasmids and microorganisms that contain these DNA fragments, methods for conferring resistance to porphyrin-accumulating type herbicides onto plant and algal cells by using these DNA fragments, and plants and algae into which these DNA fragments have been introduced for the purpose of conferring resistance to such herbicides thereon.
2. Description of Related Art
A group of widely-known compounds used as active ingredients of some varieties of commercially- and otherwise-available herbicides exhibit herbicidal activity in the presence of light, but exhibit no herbicidal activity in darkness. This has led to their common designation as light-dependent or porphyric herbicides. It has recently been shown that these herbicides induce high levels of porphyrin accumulation in plants and algae, and thus they are now designated as "porphyrin-accumulating type herbicides" [Zoku,Iyakuhin-no-Kaihatsu, (translation: "The Development of Medical Drug Products; continuation") vol. 18; Development of Agricultural Chemicals II, chapter 16, section 16-1, Hajime Iwamura, Tamio Ueno & Katsuzo Kamoshita, eds., Hirokawa Shoten, Tokyo, pubs.) or simply "porphyric herbicides". It was reported by Matringe, M., Camadro, J. M., Labbe, P. & Scalla, R. (Biochem J. 260:231 (1989)) and by Matringe, M., Camadro, J. M., Labbe, P. & Scalla, R. (FEBS Lett. 245:35 (1989)) that porphyrin-accumulating type herbicides (referred to below also as porphyric herbicides) inhibit isolated protopor-phyrinogen oxidase (referred to below as "protox").
Since most crop plants do not exhibit resistance to these porphyric herbicides, it is not possible to use these herbicides on farmland when such crops are under cultivation. If it were possible to develop crops resistant to porphyric herbicides, such herbicides could be used on these crops. This would make crop management easier, and increase the value of these herbicides in agricultural applications. For this reason, it is desirable to develop a method for conferring resistance to porphyrin-accumulating type herbicides upon crop plants.